1. Field of the Invention
The present invention relates to a method for producing acrolein by intramolecular dehydration reaction of glycerin.
2. Description of the Related Art
Bio diesel fuels produced from vegetable oils draw attentions not only as an alternative fuel of fossil fuels but also as a point of low emission of carbon dioxide, and the increase in demand is expected. Since glycerin is generated as a by-product in producing this bio diesel fuels, it is necessary to utilize the by-product. As an embodiment of use of glycerin, it can be listed that glycerin is used as a raw material for acrolein.
Production methods of acrolein using glycerin as its raw material have been already disclosed in publications.
For example, in Japanese Unexamined Patent Publication No. Hei 06-211724 (1994), there is disclosed a production of acrolein such that glycerin is dehydrated using H-ZSM-5 of MFI type zeolite having an acid strength function H0 of +2 or less. However, in the case of production of acrolein in gas phase dehydration reaction of glycerin, there is a description in the above patent publication that it is not suitable to use a catalyst with a H0 value of −8.0 or less, and in examples of the above patent publication, there is a description that reactivity of catalyst was markedly lowered in continuous use of catalyst in examples of the above patent publication.
Further, in the specification of International Publication No. WO2006-087083, there is disclosed (1) a production method of acrolein by gas phase dehydration reaction of glycerin that a catalyst prepared by mixing H-ZSM-5 of a range of −10<H0<−16 and Aerosil was used; (2) conversion rate of glycerin and yield of acrolein were lowered with passage of time.
Besides, in Le H. Dao, Reaction of Model Compounds of Biomass-Pyrolysis Oils Over ZSM-5 Zeolite Catalysts, American Chemical Society, 1988, 376, p. 328-341, it is disclosed that gas phase dehydration of glycerin was conducted using a catalyst. It is described that the catalyst used herein was composed of bentonite of 20% by mass and H-ZSM-5 of 80% by mass, and the H-ZSM-5 contained Na2O of 0.55% by mass.
As disclosed in the above publications, acrolein can be produced by dehydration of glycerin using a catalyst. In the case where yield change of acrolein with time in the production are not so large, the production plan can be easily designed, thus short or excess of the production amount of acrolein may be prevented. Further, when acrolein can be produced with a high yield, it is expected that acrolein derivatives, such as acrylic acid, 1,3-propanediol, ally alcohol, polyacrylic acid, polyacrylate and methionine, which are conventionally known to be produced from acrolein as a raw material, can be produced with low costs.